Device and method for multi-input multi-output wireless communication system

ABSTRACT

A device and method for use in a Multi-Input Multi-Output MIMO wireless communication system are provided. The device used in the MIMO wireless communication system comprises: a matching unit configured to determine a matching degree of channel estimation information of a communication device to be scheduled with one or more reference vectors included in a reference vector group, wherein the reference vector group depends on an antenna array configuration of the MIMO wireless communication system; and a channel characteristic determining unit configured to determine correlation information of the one or more reference vectors with the matching degree satisfying a predetermined condition as one or more parameters reflecting channel characteristic(s) associated with the communication device. By applying the device used in the MIMO wireless communication system and wireless communication method according to the disclosure, it is possible to avoid interference among strong-space-correlated users, and thereby improve the efficiency of processing such as scheduling, noise reduction and so on.

TECHNICAL FIELD

The disclosure generally relates to the wireless communication field, inparticular to an apparatus for use in a multi-user Multi-InputMulti-Output (MIMO) wireless communication system and a wirelesscommunication method.

BACKGROUND ART

The MIMO technology has become one of the key technologies of the nextgeneration wireless communication system. Currently, the research on apoint-to-point single-user MIMO system has been becoming mature.However, in the practical application, the system usually needs a basestation (BS) that can communicate with a plurality of user equipments(UE) simultaneously. Therefore, the research on a point-to-multipointMulti-user MIMO system has increasingly become the focus.

The Multi-user MIMO system is more complicated than the single-user AMMOsystem. Considering the fact that the application of the actualcommunication network will raise various questions in respect ofscheduling and noise reduction, the algorithm with high complexity andhigh computing cost will be involved.

Taking scheduling of users in the Multi-user MIMO system as an example,the scheduling of users in the Multi-user MIMO system may be dividedinto a selective user scheduling algorithm and a non-selective userscheduling algorithm. Exhaust algorithm and greedy search algorithm inthe selective user scheduling algorithm have better performance, but ata cost of high complexity. When the number of antennas or users islarge, the problem that the scheduling of users cannot be completed intime or the cost of computing devices is high may be caused due to itshigh complexity. The non-selective user scheduling algorithm such as aRound-Robin scheduling algorithm and a random scheduling algorithm mayresult in bad performance of the scheduling, thus fail to meet thesystem requirement.

SUMMARY OF THE INVENTION

According to one aspect of the present disclosure, there is provided adevice for use in a Multi-Input Multi-Output MIMO wireless communicationsystem, comprising: a matching unit configured to determine a matchingdegree of channel estimation information of a communication device to bescheduled with one or more reference vectors included in a referencevector group, wherein the reference vector group depends on an antennaarray configuration of the MIMO wireless communication system; and achannel characteristic determining unit configured to determinecorrelation information of the one or more reference vectors with thematching degree satisfying a predetermined condition as one or moreparameters reflecting channel characteristic(s) associated with thecommunication device.

According to another aspect of the present disclosure, there is provideda wireless communication method for a Multi-Input Multi-Output MIMOwireless communication system, the method comprising: determining amatching degree of channel estimation information of a communicationdevice to be scheduled with one or more reference vectors included in areference vector group, wherein the reference vector group depends on anantenna array configuration of the MIMO wireless communication system;and determining correlation information of the one or more referencevectors with the matching degree satisfying a predetermined condition asone or more parameters reflecting channel characteristic(s) associatedwith the communication device.

According to one aspect of the present disclosure, there is provided adevice for use in a Multi-Input Multi-Output MIMO wireless communicationsystem, comprising one or more processors configured to implement amethod comprising: determining a matching degree of channel estimationinformation of a communication device to be scheduled with one or morereference vectors included in a reference vector group, wherein thereference vector group depends on an antenna array configuration of theMIMO wireless communication system; and determining correlationinformation of one or more reference vectors with the matching degreesatisfying a predetermined condition, as one or more parametersreflecting channel characteristic(s) associated with the communicationdevice.

According to another aspect of the present disclosure, there is provideda device for user in a Multi-Input Multi-Output MIMO wirelesscommunication system, comprising: a receiving unit configured to receiveconfiguration information of an antenna array; and a generating unitconfigured to generate a reference vector group based on theconfiguration information.

According to another aspect of the present disclosure, there is provideda device for use in a Multi-Input Multi-Output MIMO wirelesscommunication system, comprising one or more processors configured toimplement a method comprising: aqcuiring configuration information of anantenna array; and generating a reference vector group based on theconfiguration information.

According to another aspect of the present disclosure, there is provideda non-transitory computer readable storage device having instructionsstored therein that when executed by processing circuitry perform acommunications method, the method comprising: determining a matchingdegree of channel estimation information of a communication device to bescheduled with one or more reference vectors included in a referencevector group, wherein the reference vector group depends on an antennaarray configuration of the MIMO wireless communication system; anddetermining correlation information of one or more reference vectorswith the matching degree satisfying a predetermined condition, as one ormore parameters reflecting channel characteristic(s) associated with thecommunication device.

The application of the device used in the MIMO wireless communicationsystem and the wireless communication method according to the presentdisclosure can avoid interference among transmissions ofstrong-space-correlated users, and thus improve the efficiency ofprocessing such as scheduling and noise reduction and so on.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the following description of the embodiments of thepresent disclosure in connection with accompanying drawings, the aboveand other purposes, characteristics and advantages of the presentdisclosure will become apparent. In the drawings, the same orcorresponding technical features or components will be indicated by thesame or corresponding reference signs. In the drawings, the sizes andrelative positions of the units are not necessarily drawn in proportion.

FIG. 1 is a block diagram illustrating a structure of a device for usein a MIMO wireless communication system according to the embodiment ofthe present disclosure.

FIG. 2 is a block diagram illustrating a structure of a schedulingdevice for use in a MIMO wireless communication system according to theembodiment of the present disclosure.

FIG. 3 is a block diagram illustrating a structure of a schedulingdevice for use in a MIMO wireless communication system according toanother embodiment of the present disclosure.

FIG. 4 is a block diagram illustrating a structure of a schedulingdevice for use in a MIMO wireless communication system according toanother embodiment of the present disclosure.

FIG. 5 is a flow chart illustrating a wireless communication method foruse in a MIMO wireless communication system according to the embodimentof the present disclosure.

FIG. 6 is a timing chart illustrating a specific example of a wirelesscommunication method for use in a MIMO wireless communication systemaccording to the embodiment of the present disclosure.

FIG. 7 is a block diagram illustrating a structure of a device forgenerating a reference vector according to the embodiment of the presentdisclosure.

FIG. 8 is a block diagram illustrating an exemplary structure capable ofimplementing a computer of the present invention.

FIG. 9 is a block diagram illustrating a first example of schematicconfigurations of the eNB to which the technology of the presentdisclosure may be applied.

FIG. 10 is a block diagram illustrating a second example of schematicconfigurations of the eNB to which the technology of the presentdisclosure may be applied.

FIG. 11 is a block diagram illustrating schematic configurations of asmart phone to which the technology of the present disclosure may beapplied.

DESCRIPTION OF EMBODIMENTS

The embodiments of the present disclosure will be illustrated withreference to the accompanying drawings. It should be noted thatexpressions and descriptions of components and processing independent ofthe present disclosure and known to those skilled in the art are omittedfor the sake of clearness.

In regard to the user scheduling in the Multi-user MIMO system, a methodis aim to maximize the throughput of the system. That is, information issent to the user when the user channel capacity reaches the maximum. Itis required to consider which user equipment in the network can becombined together at a certain time for simultaneous communication.Space division multiple access may be used in the same user group whileother access modes may be used among different groups. Therefore, it isalso required to consider spatial correlation between the users. Inaddition, it is required to seek out a compromise between effectivenessand fairness according to the characteristics and requirements of thecommunication system. Hence, one of the objects of the presentdisclosure is to provide a technology capable of avoiding interferenceamong transmissions of the strong-space-correlated users, so as to makescheduling and noise reduction with high efficiency and low costpossible.

FIG. 1 is a block diagram illustrating a structure of a device 100 foruse in a MIMO wireless communication system according to the embodimentof the present invention. The device 100 comprises a matching unit 101and a channel characteristic determining unit 102. The matching unit 101is configured to determine a matching degree between channel estimationinformation of a communication device to be scheduled and a referencevector included in a reference vector group.

The channel estimation information of the communication device may belong-term channel statistics information, e.g., but not limited to,space covariance matrix estimation. Or, the channel estimationinformation may also be real-time channel state information, e.g., butnot limited to, real-time channel state estimation.

The reference vector group is concerned with antenna arrayconfigurations of the MIMO wireless communication system. The referencevector group and the antenna array configuration information can bestored in a storage device (e.g., as a reference vector database) inadvance in association with each other so that the device 100 mayperform search.

For example, in a specific example, the communication device transmits achannel training sequence to the device 100. The device 100 estimateschannel information by receiving the channel training sequence. Inaddition, an antenna array side of the base station configured with e.g.an antenna array transmits antenna array configuration status to thedevice 100. The device 100 selects a group of reference vectors from areference vector database according to the antenna array configurations.Here, the antenna array configuration status at least comprises a numberof antennas. Besides, the antenna array configuration status may alsocomprise a geometrical shape of the antenna array and the like.

In one example, the reference vector group may comprise a plurality ofreference vectors orthogonal to one another. The plurality of referencevectors correspond to a plurality of mutually orthogonal virtual channelvectors of the antenna array. For example, in a scene of M antennas, thereference vector group can be constructed to include M orthogonalvectors. In another example, the reference vector group may comprises aplurality of reference vectors, wherein the plurality of referencevectors correspond to a plurality of virtual channel vectors of theantenna array in a maximum antenna gain direction, but not alwaysorthogonal to one another. In this example, in the scene of M antennas,as the maximum antenna gain direction may be less than M, theconstructed reference vector group does not necessarily comprise Mvectors, which are not necessarily orthogonal to one another completely.

Hereinafter, a method of determining a matching degree between channelestimation information of a communication device to be scheduled and areference vector included in a reference vector group by the matching101 will be described. The method of determining a matching degreedescribed here is only exemplary. Those skilled in the art may determinethe matching degree in various manners as appropriate.

In one example, for the user k, when a space covariance matrixestimation R_(k) is used as channel information, a matching valueλ_(m,k) corresponding to the reference vector a_(m) can be obtained byan equation (1):

λ_(m,k)=a_(m) ^(H)R_(k)a_(m)   (1)

Wherein, a_(m) is a column vector of length of M, R_(k) is a M×MHermitian matrix, and M is a number of antenna elements at a centernode.

In another example, for the user k, when a space covariance matrixestimation R_(k) is used as channel information, a matching valueλ_(m,k) corresponding to the reference vector a_(m) can be obtained byan equation (2):

λ_(m,k) |a _(m) ^(H) h _(k)|²   (2)

Wherein, v_(k) is a characteristic vector corresponding to the maximumcharacteristic value of R_(k).

In another example, for the user k, when a space covariance matrixestimation R_(k) is used as channel information, a matching valueλ_(m,k) corresponding to the reference vector a_(m) can be obtained byan equation (3):

λ_(m,k) =|a _(m) ^(H) h _(k)|²   (3)

Wherein, v_(k) and a_(m) are column vectors of length of M, and M is anumber of antenna elements at a center node.

The channel characteristic determining unit 102 is configured todetermine correlation information of the reference vector when thematching degree between the channel estimation information of thecommunication device to be scheduled and the reference vector includedin the reference vector group satisfies a predetermined condition, as aparameter reflecting a channel characteristic of the communicationdevice. Here, the predetermined condition can be determined according tosystem design. The correlation information of the reference vector whenthe matching degree satisfying the predetermined condition, as theparameter reflecting the channel characteristic, may include, forexample, identification information of the corresponding referencevector, a similarity degree between the channel estimation informationand the reference vector (e.g., a correlation value of the channelestimation information and the reference vector), and so on.

In addition, in one example, the channel characteristic determining unit201 may be configured to use the reference vector when the matchingdegree between the channel estimation information of the communicationdevice to be scheduled and the reference vector included in thereference vector group is greater than a predetermined threshold, as arepresentative vector of the communication device for specifictransmission resources, so that the parameters representing the channelcharacteristic of the communication device comprises the representativevector. In other words, correlation information of the reference vectorwhen the matching degree satisfying a predetermined condition, as aparameter of the channel characteristic, may include the referencevector itself.

In the above example, the number of representative vectors may be zero,one or plural. The direction of the representative vector of thecommunication device for specific transmission resource may be definedas a primary direction of the communication device for the specifictransmission resources, while directions corresponding to otherreference vectors may be defined as secondary directions. Eachcommunication device has zero, one or more primary directions on thespecific transmission resources. The channel having no representativevector is considered as a no-primary direction channel. The interferencecaused by data transmissions on the no-primary direction channel forother user channels can be omitted. When determining the primarydirection (i.e., the representative vector) of the communication device,the same threshold or different thresholds can be used for eachcommunication device. Assumed that some communication device has aprimary direction D_(primary)=[1] and D_(secondary)=[2, 3], wherein 1, 2and 3 are serial numbers of the direction, rather than the referencevector per se. Then, in this example, the parameters as the channelcharacteristic may also include, but not limited to, primary directionD_(primary)[1] only, or primary direction and secondary directions D=[1,2, 3], or primary direction and a similarity degree of the primarydirection, or primary direction and secondary direction and weights inthe primary and secondary directions.

The parameters of the channel characteristic of the communication deviceobtained by device 100 can reflect spatial correlation between thecommunication devices in a clean and straightforward manner, thusproviding the possibility of further implementing low-cost andhigh-efficiency scheduling and noise reduction. More specifically, inthe traditional technology, the channel estimation information is usedas complete representation of the user channel. Although the spatialcorrelation between the users may be calculated by comparing the channelestimation information, the process is very complicated, and thecalculation cost is relatively high. The device and method of thepresent disclosure may use a simple (relatively rough) method todetermine the strong-space-correlated users, thereby reducing thecalculation cost and complexity degree.

FIG. 2 is a block diagram illustrating a structure of a schedulingdevice 200 for use in a MIMO wireless communication system according tothe embodiment of the present disclosure. The scheduling device 200comprises: a matching unit 201, a channel characteristic determiningunit 202 and a communication device scheduling device 203, wherein thematching unit 201 and the channel characteristic determining unit 202have the same function and structure as those of the matching unit 101and the channel characteristic determining unit 102 as described withreference to FIG. 1. Detailed description will be omitted here. Thechannel characteristic determining unit 202 provides the obtainedparameter reflecting the channel characteristic of the communicationdevice for the communication device scheduling device 203. Thecommunication device scheduling device 203 then schedules one or more ofthe plurality of communication devices based on the channelcharacteristics of the plurality of communication devices to bescheduled. For example, the communication device scheduling device 203may schedule, with respect to specific transmission resource, the onesamong the plurality of communication devices whose differences inchannel characteristic satisfy a predetermined condition to performtransmission. For example, the communication device scheduling device203 can schedule the ones among the plurality of communication deviceswhose differences in channel characteristic are relatively larger toperform transmission.

As can be seen from the above description of the reference vector, whenthe channel characteristics of the communication devices have a highermatching degree with different reference vectors in the reference vectorgroup, respectively, differences between these channel characteristicsare greater. Therefore, in one example, the communication devicescheduling unit 203 is configured to schedule communication devices thathave no identical representative vector or have less identicalrepresentative vectors to perform transmission on the specifictransmission resource, in a case where the channel characteristicdetermining unit 202 uses the reference vector when the matching degreebeing greater than a predetermined threshold as the representativevector of the communication device for the specific transmissionresource.

The predetermined threshold, as a criterion for determining the matchingdegree, may be set in association with at least one of a channel gain, ascheduling requirement for each communication device to be scheduled anda fairness principle.

The following text will explain a specific operation of the schedulingdevice 200 according to the embodiment of the disclosure in a simpleexample. In a specific example, in a TDD and OFDM-modulated wirelesscommunication cellular system, the base station device performs along-term scheduling on user equipments within the cell by usingcovariance matrix information corresponding to the user channel on thenth resource block. The base station device is installed with a uniformlinear array formed by M antennas. The cell totally has k activesingle-antenna users. The reference vector group corresponding to theuniform linear array formed by M antennas is M DFT (discrete Fouriertransform) vectors a_(m) as illustrated in the following equation,

$\begin{matrix}{{a_{m} = {\frac{1}{\sqrt{M}}\left\lbrack {1,^{{j\psi}_{m}},\ldots \mspace{14mu},^{{j{({M - 1})}}\psi_{m}}} \right\rbrack}^{T}},{\psi_{m} = \frac{2\pi \; m}{M}},{m = 0},\ldots \mspace{14mu},{M - 1.}} & (4)\end{matrix}$

The covariance matrix estimation on the nth resource block correspondingto the user equipment k is represented by R_(k,n), and thus the matchingvalue λ_(m,k,n) corresponding to the reference vector a_(m) iscalculated as

λ_(m,k,n)=a_(m) ^(H)R_(k,n)a_(m)   (5)

Assuming a threshold of σ, for λ_(m,k,n) greater than σ, m is recordedas a primary direction index number corresponding to the channel of theuser k on the source block n.

A user with such corresponding primary direction is searched from m=0,and m is sequentially increased until m=M-1. If there are a plurality ofusers who take the primary direction with the same index number m as oneof the primary directions, the primary user with the maximumcorresponding value λ_(m,k,n) is selected therefrom and scheduled, andthe remaining users are marked as users who are not scheduled, thuspreventing the strong-space-correlated users from being scheduled to thesame transmission resource, and further reducing the interference andimproving the transmission efficiency. In another example, if there area plurality of users who take the primary direction with the same indexnumber m as one of the primary directions, the primary user with themaximum corresponding value w_(k)λ_(m,k,n) is selected therefrom andscheduled, and the remaining users are marked as users who are notscheduled. Here, w_(k) is a scheduling weight for the user. For example,it depends on a scheduling priority of the user (e.g., related to theservice type), and scheduling requirement (e.g., related to the waitingscheduling time). In addition, in another example, the threshold σ isset relatively low, so the user k has multiple primary directions m, band c, and the multiple primary directions are then arranged in adescending order according to the matching values corresponding to thecorresponding reference vectors. For instance, the channel estimationfor user k has the maximum matching value with the reference vectora_(m), only the users who take the primary direction with the same indexnumber m as a primary direction and arrange the same in the first placeamong a plurality of primary directions will be considered. Thenschedule is performed in accordance to the above two examples. Thoseskilled in the art could design other simple variants based on the aboveexamples, which are not illustrated herein.

In the above example, the reference vector {am} is constructed inaccordance to M virtual channel vectors of the antenna array which areorthogonal to one another. Alternatively, the plurality of referencevectors in the reference vector group correspond to virtual channelvectors of the antenna array comprising M antenna elements in aplurality of maximum antenna gain directions. For example, the pluralityof maximum antenna gain directions is determined by experiments ortrainings in advance, and then the reference vectors are constructedaccordingly. The vectors included in the reference vector groupconstructed in such a manner do not orthogonal to one anothercompletely, and the number of the vectors is less than M.

FIG. 3 is a block diagram illustrating a structure of a schedulingdevice 300 for use in a MIMO wireless communication system according toanother embodiment of the present disclosure. The scheduling device 300comprises: a matching unit 301, a channel characteristic determiningunit 302, a communication device scheduling unit 303 and a pre-encodingmatrix generating unit 304, wherein the matching unit 301 and thechannel characteristic determining unit 302 have the same function andstructure as those of the matching unit 201 and the channelcharacteristic determining unit 202 as described with reference to FIG.2. Detailed description will be omitted here.

In a preferred example, like the corresponding description for FIG. 2,the communication device scheduling unit 303 schedules communicationdevices having different representative vectors to perform transmissionon the specific transmission resource. The pre-encoding matrixgenerating unit 304 generates a pre-encoding matrix based on channelestimation information of the communication devices in the conventionalmanner for example. For example, a channel matrix constructed by usingchannels of the communication devices which are scheduled to performtransmission on the same time-frequency resource is subjected to azero-forcing algorithm, and thus a pre-encoding matrix is obtained.

In an optional example, in a case where the channel characteristicdetermining unit 302 takes a reference vector having a matching degreegreater than the predetermined threshold as the representative vector ofthe communication devices for specific transmission resource, and thecommunication device scheduling unit 303 schedules the communicationdevices having identical representative vectors to perform transmissionon the specific transmission resource, the pre-encoding matrixgenerating unit 304 may be configured to calculate a pre-encoding matrixfor the communication devices having identical representative vectorsbased on the channel characteristics, so as to reduce interference tothe communication devices having identical representative vectors. Inthe example in which the communication device has a plurality ofrepresentative vectors, the scheduling unit 303 may also schedule thecommunication devices having partial identical representative vectors(i.e., a case where the representative vectors are overlapped), and thepre-encoding matrix generating unit 304 may be configured to calculate apre-encoding matrix for the communication devices having the overlappedrepresentative vectors based on the channel characteristics, so as toreduce interference to the communication devices having the overlappedrepresentative vectors.

The specific calculation method of the pre-encoding matrix generatingunit 304 of the scheduling device 300 according to the embodiment of thedisclosure is described in a simple example as follows. The pre-encodingmatrix generating unit 304 may calculate the pre-encoding matrix usingany methods according to the requirement of the system.

In one specific example, assuming two users, i.e., user 0 and user 1,and assuming that the base station has eight antennas and thecorresponding reference vector is {v_(m)}v_(m)=0, . . . ,7, therepresentative vector corresponding to the downlink channel vector h₀ ofuser 0 is D₀=[1, 2, 3] and the corresponding weight is {w_(0,1),w_(0,2), w_(0,3)}. A representative vector corresponding to the downlinkchannel vector h₁ of user 1 is D₁=[3, 4, 5], and the correspondingweight is {w_(1,3), w_(1,4), w_(1,5)}. Wherein, the weight isrepresented by a matching value with the corresponding reference vectorfor example. Assuming w_(0,3)>w_(1,3), the pre-encoding submatrixcorresponding to the user channel h₀ is p₀=h₀ ^(H), and the pre-encodingsubmatrix corresponding to the user channel h₁ is p₁=(I−v₃v₃ ^(H))h₁^(H). Wherein, I is a unit matrix having the same number of dimensionsas v₃v₃ ^(H). The pre-encoding matrix employed by the base station (andconstructed by the pre-encoding matrix generating unit 304) is

$\begin{matrix}{p = {\frac{\left\lbrack {p_{0},p_{1}} \right\rbrack}{\left\lbrack {p_{0},p_{1}} \right\rbrack }.}} & (6)\end{matrix}$

Next, a principle of constructing a pre-encoding matrix by using theequation (6) is simply explained. There exists interference between user0 and user 1 because both of them use vector 3 as the representativevector. As user 0 has a larger weight on the representative vector 3,user 0 can hold the representative vector 3. User 1 evades direction 3by projecting the pre-encoding matrix onto an orthogonal spacecorresponding to the representative vector 3, thereby avoidinginterference to user 0.

In the example described with reference to FIG. 3, scheduling of thecommunication devices is performed by using parameters reflectingchannel characteristics of the communication devices determined by thechannel characteristic determining unit 302, and pre-encoding isperformed for data transmission of the communication devices that arescheduled in this manner. Thus, the scheduling efficiency is improved,and the transmission interference between the communication deviceshaving identical representative vectors is reduced. In anotherembodiment, pre-encoding is also performed by using parametersreflecting channel characteristics of the communication devicesdetermined by the channel characteristic determining unit 302 for datatransmission of the communication devices scheduled in accordance totraditional scheduling methods, thus reducing the transmissioninterference between the communication devices.

FIG. 4 is a block diagram illustrating a structure of a schedulingdevice 400 for use in a MIMO wireless communication system according toanother embodiment of the present disclosure. The scheduling device 400comprises: a matching unit 401, a channel characteristic determiningunit 402 and a pre-encoding unit 403, wherein the matching unit 401 andthe channel characteristic determining unit 402 have the same functionand structure as those of the matching unit 101 and the channelcharacteristic determining unit 102 as described with reference toFIG. 1. Detailed description will be omitted here. For a plurality ofcommunication devices to be scheduled simultaneously, the pre-encodingunit 403 can perform pre-encoding on the transmission data of thescheduled communication devices based on the channel characteristics ofthe plurality of communication devices. Specifically, the pre-encodingunit 403 may perform pre-encoding processing by using the pre-encodingmatrix calculated in the same way as the pre-encoding matrix generatingunit 304 (or the pre-encoding matrix generated by the pre-encodingmatrix generating unit is directly used in the scheduling device 400),thus eliminating the interference between the communication devices. Thedetailed description is omitted here.

FIG. 5 is a flow chart illustrating a wireless communication method foruse in a MIMO wireless communication system according to the embodimentof the present disclosure. The wireless communication method can be usedby e.g. device 100 described in connections with FIG. 1. In step S501, amatching degree between the channel estimation information of thecommunication device to be scheduled and the reference vector includedin the reference vector group is determined. Here, the channelestimation information may either be long-term channel statisticsinformation or channel status information. The reference vector group isassociated with antenna array configuration of the MIMO wirelesscommunication system. In one example, the reference vector group mayinclude a plurality of reference vectors which are orthogonal to oneanother, wherein the plurality of reference vectors corresponds to aplurality of virtual channel vectors of the antenna array which areorthogonal to one another. In another example, the reference vectorgroup may include a plurality of reference vectors, wherein theplurality of reference vectors correspond to virtual channel vectors ofthe antenna array in a plurality of maximum antenna gain directions.

In one embodiment, a reference vector with the matching degree greaterthan a predetermined threshold is determined as a representative vectorof the communication device for the specific transmission resource, andfurther as a parameter reflecting the channel characteristic of thecommunication device.

In step S502, correlation information of the reference vector with thematching degree satisfying a predetermined condition is determined as aparameter reflecting a channel characteristic of the communicationdevice.

The specific operation example of the method as shown in FIG. 5 has beendescribed in detail in connection with FIG. 1, thus the description isomitted here. When the parameter reflecting the channel characteristicof the communication device is obtained using the method described inFIG. 5, scheduling of the communication device and elimination of theinterference can be performed based on the parameter as described above.A specific example will be described in connection with FIG. 6 asfollows.

FIG. 6 is a timing chart illustrating a specific example of a wirelesscommunication method for use in a MIMO wireless communication systemaccording to the embodiment of the present disclosure. The wirelesscommunication method according to the embodiment of the presentdisclosure is not limited to the embodiment. For example, but notlimited to, the sequence executed in some steps in FIG. 6 can be changedas appropriate, or some steps can be omitted or executed in parallel.

As shown in FIG. 6, in operation T1, an antenna array side transmitsconfiguration information of an antenna array to the scheduling deviceaccording to the embodiment of the present disclosure. According toapplication scenarios, the antenna array side may be, e.g., RRHconfigured with an antenna array, a relay station, or a primary userequipment configured with an antenna array in a Device-to-Devicescenario. The antenna array side of the embodiment of the presentdisclosure is a transmitting side or a receiving side for datatransmission, and the scheduling processing may include forward/downlinkscheduling and backward/uplink scheduling. The configuration informationof the antenna array may include: information on the number of antennas,geometric shape information of the antenna array, etc. The schedulingdevice according to the embodiment of the present disclosure can bedisposed separately from the antenna array side (for example, eNB havinga scheduler performs transmission control for the RRH having the antennaarray), or can be integrated with the antenna array side (for example,eNB having an antenna array and a scheduler performs transmissioncontrol for the antenna array thereof). In the example that thescheduling device and the antenna array side are disposed separately,operation T1 is executed through the corresponding communicationinterface. In the example that the scheduling device and the antennaarray side are integrated into a whole, operation T1 is executed throughe.g. RF cables. In addition, in operation T1, instead of theconfiguration information of the antenna array, the antenna array sidemay transmit identification information such as a serial number of theantenna array side to the scheduling device, and the scheduling devicemay retrieve the corresponding configuration information of the antennaarray from a pre-stored database.

After the scheduling device receives the configuration information ofthe antenna array, in operation T2, the scheduling device may select areference vector group based on the corresponding configurationinformation.

In operation T3, the user equipment (as an example of the “communicationdevice”) transmits to the scheduling device a channel training sequence,for example, a Sounding Reference Signal in an LTE system, and otherpilot signals.

In operation T4, the scheduling device estimates channel information ofthe user equipment based on the received channel training sequence. Thechannel information may either be real-time channel status informationor long-term channel statistics information.

After the reference vector group is determined and the channelinformation is estimated, in operation T5, the scheduling devicedetermines a matching degree between them. The method of determining amatching degree has been described exemplarily in the above, so thedescription is omitted here. The matching degree can reflect the channelcharacteristic of the user equipment. In other words, when the matchingdegree satisfies a predetermined condition, correlation information ofthe corresponding reference vector can reflect the channelcharacteristic of the user equipment.

In operation T6, user equipment to be scheduled to perform transmissionon the same transmission resource can be selected based on the obtainedchannel characteristic. For example, the ones among the plurality ofcommunication devices whose differences in channel characteristicsatisfy a predetermined condition may be selected. In a case where thereference vector with a matching degree greater than a predeterminedthreshold is used as a representative vector of the user equipment forthe specific transmission resource and further used as a parameterreflecting the channel characteristic of the communication device, userequipments that have no identical representative vector or haverelatively less identical representative vectors may be selected toperform transmission on the specific transmission resource. Here, thepredetermined threshold is set in association with at least one of achannel gain, a scheduling requirement for each communication device tobe scheduled, and a fairness principle.

In operation T7, the scheduling device transmits scheduling informationto the user equipment selected in operation T6.

In operation T8, the user equipment receives scheduling information fromthe scheduling device and initiates the corresponding data transmission.Specifically, the user equipment may perform downlink reception anduplink transmission respectively based on whether the schedulinginformation is downlink scheduling information or uplink schedulinginformation.

Although it is not shown in FIG. 6, the wireless communication methodaccording to the embodiment of the present disclosure may also performpre-encoding on transmission data of the scheduled communication devicesbased on channel characteristics of a plurality of communication devicesscheduled simultaneously, so as to reduce interference among thecommunication devices. The same process applies to the communicationdevices scheduled by using traditional scheduling methods. In addition,in a case where the scheduling method according to the embodiment of thepresent disclosure is used and communication devices having identicalrepresentative vectors are scheduled to perform transmission on thespecific transmission resource, a pre-encoding matrix for thecommunication devices having identical representative vectors can becalculated based on the channel characteristics, so as to reduceinterference among the communication devices having identicalrepresentative vectors.

The wireless communication method in the Multi-Input Multi-Output (MIMO)wireless communication system according to the embodiment of the presentdisclosure as described above may be performed by one or more processorsof a device.

FIG. 7 is a block diagram illustrating a structure of a device 700 foruse in a MIMO wireless communication system according to the embodimentof the present disclosure. The device 700 comprises a receiving unit 701and a generating unit 702, wherein the receiving unit 701 is used forreceiving configuration information of an antenna array, the generatingunit 702 is used for generating a reference vector group based onconfiguration information. Reference vectors in the reference vectorgroup generated by the generating unit 702 may be e.g. orthogonal to oneanother, or correspond to respective maximum antenna gain directions ofthe antenna array respectively.

In one embodiment, the generating unit 702 may generate a referencevector group based on at least information on the number of antennas inthe configuration information. The number of dimensions of the referencevectors in the reference vector group may be equal to the number ofantennas. In another embodiment, the generating unit 702 may alsogenerate a reference vector group based on information relating to thegeometrical shape of the antenna array in the configuration information.A processing of generating a reference vector group by the generatingunit 702 based on the antenna configuration information is described asfollows.

In one example, for a uniform linear antenna array formed by M antennaelements having identical polarization direction, the generating unit702 may generate M reference vectors which are orthogonal to oneanother. Here, each reference vector may be a DFT vector. That is,reference vector r_(m) is in a form as shown in equation (7):

$\begin{matrix}{{r_{m} = {\frac{1}{\sqrt{M}}\left\lbrack {1,\ldots \mspace{14mu},^{\frac{{{j2\pi}{({i - 1})}}m}{M}},\ldots \mspace{14mu},^{\frac{{{j2\pi}{({M - 1})}}m}{M}}} \right\rbrack}^{T}},} & (7)\end{matrix}$

wherein m is a serial number of the reference vector, and i is alocation number of a element constituting the vector component.

In another example, in a scenario of a clustered linear antenna arrayformed by a uniform arrangement of M/2 antenna clusters, assuming thateach antenna cluster is consisted of a pair of antenna elements whosepolarization directions are orthogonal to each other, and that theantenna array is divided into two groups of common-polar subarraysaccording to the polarization direction, the generating unit maygenerate M reference vectors, so that each reference vector of a lengthof M is consisted of two groups of DFT vectors, which are orthogonal toeach other and each of which has a length of M/2. That is, referencevector r_(m) is in a form as shown in equation (8):

$\begin{matrix}{r_{m} = \left\{ {\begin{matrix}{{\frac{1}{\sqrt{2M}}\left\lbrack {p_{m},{^{j\alpha}q_{m}}} \right\rbrack}^{T},{{0 \leq m \leq {\frac{M}{2} - 1}};}} \\{{\frac{1}{\sqrt{2M}}\left\lbrack {p_{m - \frac{M}{2}},{{- ^{j\alpha}}q_{m - \frac{M}{2}}}} \right\rbrack}^{T},{\frac{M}{2} \leq m \leq {M - 1}}}\end{matrix},} \right.} & (8)\end{matrix}$

wherein m is a serial number of the reference vector, α is anon-negative real number with a value between 0 and 2π, and p_(m) andq_(m) are sub-reference vectors respectively. For example, a M×M/2matrix formed by arranging sub-reference vectors p_(m) in order may be amatrix formed by arranging sub-reference vectors q_(m) in order orcommutation of the matrix.

In another example, for a uniform planar antenna array formed by M×Nantenna elements having identical polarization direction, there are M×Nreference vectors of a length of M×N. Wherein, each reference vectorr_(m,n) is a Kronecker product of two DFT vectors r_(m) and r_(n) asshown in equation (7) which have lengths M and N respectively. That is,reference vector r_(m,n) is in a form as shown in equation (9):

r _(m,n) =r _(m) {circle around (×)}r _(n)   (9),

Wherein r_(m) and r_(n) are DFT vectors calculated according to equation(7).

In another example, for a clustered planar antenna array formed by auniform arrangement of M/2×N antenna clusters each of which is consistedof a pair of antennal elements which are orthogonal to each other inpolarization directions, the antenna array is divided into two groups ofcommon-polar subarrays according to the polarization direction. Thereare M×N reference vectors of a length of M×N. Each reference vectorr_(m,n) is a Kronecker product of a DFT vector r_(m) having a length ofM calculated according to equation (8) and a DFT vector r_(n) having alength of N calculated according to equation (7).

The present invention is described above with reference to the flowcharts and/or block diagrams of methods and devices according to theembodiments of the present invention. It should be noted thatexpressions and descriptions of components and processes which areirrelevant to the present invention and known to those skilled in theart are omitted in the drawings and description for the sake of clarity.Each block of the flow chart and/or block diagram as well as acombination of various blocks of the flow chart and/or block diagram canbe implemented by computer instructions. The computer instructions maybe provided to general purpose computers, special purpose computers orother processors of programmable data processing devices. Thereby, amachine can be produced so that these instructions executed by acomputer or other programmable data processing devices can produce adevice for implementing functions/operations specified in the blocks ofthe flow chart and/or block diagram.

These computer program instructions may also be stored in acomputer-readable medium capable of instructing a computer or otherprogrammable data processing devices to operate in a particular way. Inthis way, the instructions stored in the computer-readable mediumgenerate a manufacture comprising an instruction means for implementingfunctions/operations specified in the blocks of the flow chart and/orblock diagram.

These computer program instructions may also be loaded onto a computeror other programmable data processing devices, so that a series ofoperation steps are executed on the computer or other programmable dataprocessing devices to generate a computer-implemented process, andthereby the instructions executed on the computer or other programmabledevices may provide a process for implementing the functions/operationsspecified in the blocks of the flow chart and/or block diagram.

It should be understood that the flow charts and block diagramsillustrate system architecture, function and operation that may beimplemented by the system, method and computer program product accordingto various embodiments of the present invention. On this point, eachblock of the flow chart or the block diagram represents a module, aprogram segment, or a part of codes. The module, the program segment, orthe part of codes includes one or more executable instructions forimplementing the specified logic functions. It should also be notedthat, in some alternative implementations, functions marked in theblocks may also be implemented in an order which is different from thatmarked in the drawing. For example, two consecutive blocks can actuallybe implemented substantially in parallel, and sometimes can beimplemented in a reverse order, depending on the involved functions. Itshould also be noted that each block in the block diagram and/or flowchart as well as a combination of blocks in the block diagram and/orflow chart may be implemented by a special-purpose hardware-based systemfor implementing the specified functions or operations, or by acombination of special-purpose hardware and computer instructions.

FIG. 8 is a block diagram illustrating an exemplary structure capable ofimplementing a computer of the present invention. In FIG. 8, a centralprocessing unit (CPU) 801 performs various processes according toprogram stored in an ROM 802 or program loaded from a storage section808 onto an RAM 803. In RAM 803, data required for CPU 801 performingvarious processes may also be stored as appropriate.

CPU 801, ROM 802 and RAM 803 are connected to one another via a bus 804.An input/output interface 805 is also connected to the bus 804.

The following components are connected to the input/output interface805, i.e., an input section 806 including a keyboard, a mouse, etc.; anoutput section 807 including a display, such as a CRT, an LCD, and aloudspeaker, etc.; a storage section 808 including a hard disk, etc.;and a communication section 809 including a network interface card, suchas a LAN card, a modem, etc. The communication section 809 performscommunication process via e.g. internet.

A driver 810 is also connected to the input/output interface 805 asappropriate. Removable media 811 such as a disc, an optical disc, amagneto-optical disk, a semiconductor memory, etc. are installed on thedriver 810 as appropriate, so that computer programs read therefrom areinstalled into the storage section 808 as appropriate.

In case of implementing the above steps and processes through software,programs of the software are installed from a network such as internetor a storage medium such as the removable media 811.

Those skilled in the art should understand that such storage media arenot limited to the removable media 811 storing programs therein anddistributed separately from the device to provide the user withprograms. Examples of the removable media 811 comprise disk, opticaldisk (including CD-ROM and DVD), magneto-optical disk (including MD) andsemiconductor memory. Or, storage media may be ROM 802, a hard diskincluded in the storage section 808, etc. It has program stored therein,and is distributed to the user together with the device including it.

According to the embodiment of the present disclosure, the base stationmay be implemented to be e.g. in any type of eNB, such as macro eNB andmicro eNB. The micro eNB can cover eNB of a cell that is smaller than amacro cell, such as micromicro eNB, micro eNB and home (femto) eNB.Alternatively, the base station may be implemented to be in any othertype of base station, such as NodeB and BTS. The base station mayinclude: a main body (which is also called base station device)configured to control wireless communication; and one or more remotewireless head end (RRH) disposed in a location different from that ofthe main body, wherein, as the development of Centralized, Cooperative,Cloud RAN (C-RAN), the aforementioned main body for controlling wirelesscommunication may also be a cloud baseband processing device, e.g., aserver. In addition, various types of terminals to be described belowmay function as base stations by implementing the functions of the basestations temporarily or semipersistently.

The user equipment according to the present disclosure can be e.g.implemented as a mobile terminal (such as a smart phone, a tablet PC, anotebook PC, a smart wearable device, a portable game terminal, aportable/FreeEIM type mobile router, and a digital camera device) or avehicle-mounted terminal (such as automobile navigation equipment). Theuser equipment may also be implemented as a terminal for implementingMachine-to-Machine (M2M) communication (which is also called a machinetype communication (MTC) terminal). In addition, the user equipment maybe a wireless communication module (such as an integrated circuit moduleincluding a single chip) installed on each of the above terminals.

An application example of a base station and user equipment will bedescribed in connection with FIGS. 9 to 11.

FIG. 9 is a block diagram illustrating a first example of schematicconfigurations of the eNB to which the technology of the presentdisclosure may be applied. eNB 900 includes one or more antennas 910 andbase station device 920. The base station device 920 and each antenna910 are connected to each other via RF cables.

Each of the antennas 910 comprises single or multiple antenna elements(such as a plurality of antenna elements included in the MIMO antenna),and is used for transmitting and receiving wireless signals for the basestation device 920. As shown in FIG. 9, eNB 900 may include a pluralityof antennas 910. For example, the plurality of antennas 910 may becompatible with a plurality of frequency bands used by eNB 900. AlthoughFIG. 9 shows therein an example that the eNB 900 comprises a pluralityof antennas 910, eNB 900 may also include a single antenna 910.

The base station device 920 comprises a controller 921, a memory 922, anetwork interface 923 and a wireless communication interface 925.

The controller 921 may be e.g. CPU or DSP, and performs variousfunctions of higher layers of the base station device 920. For example,the controller 921 generates a data packet based on data in the signalsprocessed by the wireless communication interface 925, and transmits thegenerated packet via the network interface 923. The controller 921 canbind data from a plurality of baseband processors to generate a bindingpacket, and transmit the generated binding packet. The controller 921may have logic functions for executing the controls such as radioresource control, radio bearer control, mobility management, admissioncontrol and scheduling. The controls can be implemented in combinationwith neighboring eNB or core network. The memory 922 comprises RAM andROM, and stores programs executed by the controller 921 and varioustypes of control data (such as a terminal list, transmission power dataand scheduling data).

The network interface 923 is a communication interface for connectingthe base station device 920 to a core network 924. The controller 921may communicate with the core network node or another eNB via thenetwork interface 923. In this case, eNB 900 and the core network nodeor other eNB can be connected to each other through a logic interface(such as an ST interface and an X2 interface). The network interface 923may also be a wired communication interface or a wireless communicationinterface for a wireless backhaul line. If the network interface 923 isa wireless communication interface, the network interface 923 may use ahigher frequency band for wireless communication compared with thefrequency band used by the wireless communication interface 925.

The wireless communication interface 925 supports any cellularcommunication schemes (such as LTE and LTE-advanced), and provides towireless communication located in a terminal of a cell in eNB 900 viathe antennas 910. The wireless communication interface 925 may usuallycomprise e.g. a baseband (BB) processor 926 and an RF circuit 927. TheBB processor 926 may perform e.g. encoding/decoding,modulation/demodulation and multiplexing/demultiplexing, and perform alltypes of signal processing for the layers (for example, L1, media accesscontrol (MAC), radio link control (RLC) and packet data convergenceprotocol (PDCP)). The BB processor 926, in place of the controller 921,may have a part of or all of the above logic functions. The BB processor926 may be a memory for storing communication control programs, or amodule comprising a processor configured to execute programs and relatedcircuits. Updating the programs may change the functions of the BBprocessor 926. The module may be a card or a blade inserted into a slotof the base station device 920. Alternatively, the module may also be achip mounted on a card or a blade. Meanwhile, the RF circuit 927 maycomprise e.g. a frequency mixer, a filter and an amplifier, and transmitand receive an antenna signal via the antennas 910.

As shown in FIG. 9, the wireless communication interface 925 maycomprise a plurality of BB processors 926. For example, the plurality ofBB processors 926 may be compatible with a plurality of frequency bandsused by eNB 900. As shown in FIG. 9, the wireless communicationinterface 925 may comprise a plurality of RF circuits 927. For example,the plurality of RF circuits 927 may be compatible with the plurality ofantenna elements. Although FIG. 9 shows therein an example that thewireless communication interface 925 comprises a plurality of BBprocessors 926 and a plurality of RF circuits 927, the wirelesscommunication interface 925 may also include a single BB processor 926or a single RF circuit 927.

FIG. 10 is a block diagram illustrating a second example of schematicconfigurations of the eNB to which the technology of the presentdisclosure may be applied. eNB 1000 comprises one or more antennas 1010,base station device 1020 and RRH 1030. RRH 1030 and each antenna 1010can be connected to each other via RF cables. Base station device 1020and RRH 1030 can be connected to each other via a high speed line suchas optical fiber cable.

Each of antennas 1010 comprises single or multiple antenna elements(such as a plurality of antenna elements included in the MIMO antenna)and is used for transmitting and receiving wireless signals for RRH1030. As shown in FIG. 10, eNB 1000 may comprise a plurality of antennas1010. For example, the plurality of antennas 1010 may be compatible witha plurality of frequency bands used by eNB 1000. Although FIG. 10 showstherein an example that the eNB 1000 comprises a plurality of antennas1010, eNB 1000 may also include a single antenna 1010.

The base station device 1020 comprises a controller 1021, a memory 1022,a network interface 1023, a wireless communication interface 2015 and aconnection interface 1027. The controller 1021, the memory 1022 and thenetwork interface 1023 are identical to the controller 921, the memory922 and the network interface 923 as described with reference to FIG. 9.The network interface 1023 is used for connecting the base stationdevice 1020 to a core network 1024.

The wireless communication interface 1025 supports any cellularcommunication schemes (such as LTE and LTE-advanced), and provideswireless communication to a terminal located in a sector correspondingto RRH 1030 via the RRH 1030 and the antenna 1010. The wirelesscommunication interface 1025 may usually comprise e.g. a BB processor1026. The BB processor 1026 is the same as the BB processor 926 asdescribed with reference to FIG. 9, except that the BB processor 1026 isconnected to the RF circuit 1034 of the RRH 1030 via the connectioninterface 1027. As shown in FIG. 10, the wireless communicationinterface 1025 may comprise a plurality of BB processors 1026. Forexample, the plurality of BB processors 1026 may be compatible with aplurality of frequency bands used by eNB 1000. Although FIG. 10 showstherein an example that the wireless communication interface 1025comprises a plurality of BB processors 1026, the wireless communicationinterface 1025 may also include a single BB processor 1026.

The connection interface 1027 is an interface for connecting the basestation device 1020 (the wireless communication interface 1025) to theRRH 1030. The connection interface 1027 may also be a communicationmodule for connecting the base station device 1020 (the wirelesscommunication interface 1025) to communication in the above high speedline of the RRH 1030.

The RRH 1030 comprises a connection interface 1031 and a wirelesscommunication interface 1033.

The connection interface 1031 is an interface for connecting the RRH1030 (the wireless communication interface 1033) to the base stationdevice 1020. The connection interface 1031 may also be a communicationmodule for the communication in the above high speed line.

The wireless communication interface 1033 transmits and receiveswireless signals via the antennas 1010. The wireless communicationinterface 1033 may usually comprise e.g. an RF circuit 1034. The RFcircuit 1034 may include e.g. a frequency mixer, a filter and anamplifier, and transmit and receive wireless signals via the antennas1010. As shown in FIG. 10, the wireless communication interface 1033 maycomprise a plurality of RF circuits 1034. For example, the plurality ofRF circuits 1034 may support the plurality of antenna elements. AlthoughFIG. 10 shows an example in which the wireless communication interface1033 comprises a plurality of RF circuits 1034, the wirelesscommunication interface 1033 may also include a single RF circuit 1034.

In the eNB 900 and eNB 1000 as shown in FIGS. 9 and 10, thetransmissions performed in operations T1 and T7 as described in theexample of FIG. 6 and the function of the receiving unit 701 asdescribed in the example of FIG. 7 can be implemented by the wirelesscommunication interface 925 and the wireless communication interface1025 and/or the wireless communication interface 1033. At least a partof the functions may also be implemented by the controllers 921 and1021. For example, the device 100 implemented in the example of FIG. 1can perform the function of the matching unit 101 and the channelcharacteristic determining unit 102 through the controller 921 or thecontroller 1021. In addition, the functions of various units of thedevices 200-400 implemented in the examples of FIGS. 2 to 4 respectivelymay also be performed by the controller 921 or the controller 1021. Inaddition, the function of the generating unit 702 of the referencevector generating unit 700 implemented by the example of FIG. 7 may alsobe performed by the controller 921 or the controller 1021.

FIG. 11 is a block diagram illustrating schematic configurations of asmart phone 1100 to which the technology of the present disclosure maybe applied. The smart phone 1100 comprises a processor 1011, a memory1102, a storage device 1103, an external connection interface 1104, acamera device 1106, a sensor 1107, a microphone 1108, an input device1109, a display device 1110, a loudspeaker 1111, a wirelesscommunication interface 1112, one or more antenna switches 1115, one ormore antennas 1116, a bus 1117, a battery 1118 and an auxiliarycontroller 1119.

The processor 1101 may be e.g. CPU or System on Chip (SoC), and controlthe functions of an application layer and other layers of the smartphone. The memory 1102 comprises RAM and ROM, and stores data andprograms executed by the processor 1101. The storage device 1103 maycomprise a storage medium, such as a semiconductor memory and a harddisk. The external connection interface 1104 is an interface forconnecting an external device (such as a memory card and a USB device)to the smart phone 1100.

The camera device 1106 comprises an image sensor (such as a CCD and aCMOS), and generates a captured image. The sensor 1107 may comprise aset of sensors, such as measuring sensors, gyro sensors, geomagneticsensors and acceleration sensors. The microphone 1108 converts a voiceinputted into the smart phone 1100 into an audio signal. The inputdevice 1109 comprises e.g. a touch sensor, a keypad, a keyboard, abutton or a switch configured to detect a touch on a screen of thedisplay device 1110, and receives input operation or information fromthe user. The display device 1110 comprises the screen (such as an LCDand an OLED display), and displays an image outputted from the smartphone 1100. The loudspeaker 1111 converts the audio signal outputtedfrom the smart phone 1100 into sound.

The wireless communication interface 1112 supports any cellularcommunication schemes (such as LTE and LTE-advanced), and performswireless communication. The wireless communication interface 1112 mayusually comprise e.g. a BB processor 1113 and an RF circuit 1114. The BBprocessor 1113 may perform e.g. encoding/decoding,modulation/demodulation and multiplexing/demultiplexing, and perform alltypes of signal processing for wireless communications. Meanwhile, theRF circuit 1114 may comprise e.g. a frequency mixer, a filter and anamplifier, and transmit and receive a radio signal via the antenna 1116.The wireless communication interface 1112 may be a chip module havingthe BB processor 1113 and the RF circuit 1114 integrated thereon. Asshown in FIG. 11, the wireless communication interface 1112 may comprisea plurality of BB processors 1113 and a plurality of RF circuits 1114.Although FIG. 11 shows an example in which the wireless communicationinterface 1112 comprises a plurality of BB processors 1113 and aplurality of RF circuits 1114, the wireless communication interface 1112may also include a single BB processor 1113 or a single RF circuit 1114.

Besides, in addition to the cellular communication scheme, the wirelesscommunication interface 1112 may support other types of wirelesscommunication schemes, such as a short-range wireless communicationscheme, a near field communication scheme, and a wireless LAN scheme. Inthis case, the wireless communication interface 1112 may comprise a BBprocessor 1113 and an RF circuit 1114 for each type of wirelesscommunication scheme.

Each of the antenna switches 1115 switches connection destinations ofthe antennas 1116 among a plurality of circuits included in the wirelesscommunication interface 1112 (e.g., the circuit for different wirelesscommunication schemes).

Each of the antennas 1116 comprises single or multiple antenna elements(such as a plurality of antenna elements included in the MIMO antenna),and is used for transmitting and receiving wireless signals for thewireless communication interface 1112. As shown in FIG. 11, the smartphone 1100 may include a plurality of antennas 1116. Although FIG. 11shows an example in which the smart phone 1100 comprises a plurality ofantennas 1116, the smart phone 1100 may also include a single antenna1116.

Besides, the smart phone 1100 may comprise antennas 1116 for each typeof wireless communication scheme. In this case, the antenna switches1115 may be omitted from the configurations of the smart phone 1100.

The bus 1117 is used for connecting the processor 1101, the memory 1102,the storage device 1103, the external connection interface 1104, thecamera device 1106, the sensor 1107, the microphone 1108, the inputdevice 1109, the display device 1110, the loudspeaker 1111, the wirelesscommunication interface 1112, and an auxiliary controller 1119 with oneanother. The battery 1118 provides an electric power for each block ofthe smart phone 1100 as shown in FIG. 11 via feeding lines. The feedinglines are partially illustrated as dotted lines in the figure. Theauxiliary controller 1119 performs the minimum required function of thesmart phone 1100 in a sleep mode.

In a Device-to-Device scenario, for example, for the smart phone 1100 asshown in FIG. 11, the transmissions performed in operations T1 and T7 asdescribed in the example of FIG. 6 and the function of the receivingunit 701 as described in the example of FIG. 7 can be implemented by thewireless communication interface 1112. At least a part of the functionsmay also be implemented by the controllers 1101 or the auxiliarycontroller 1119, respectively. For example, the device 100 implementedin the example of FIG. 1 can perform the function of the matching unit101 and the channel characteristic determining unit 102 through theprocessor 1101 or the auxiliary controller 1119. In addition, thefunctions of various units of the devices 200-400 implemented in theexamples of FIGS. 2 to 4 respectively may also be performed by theprocessor 1101 or the auxiliary controller 1119. In addition, thefunction of the generating unit 702 of the reference vector generatingunit 700 implemented in the example of FIG. 7 may also be performed bythe processor 1101 or the auxiliary controller 1119.

It should be understood that the terms used in the disclosure are onlyaim to describe the specific embodiments, but not intended to limit thepresent invention. The wordings “one” or “the” in a singular form usedin the disclosure are intended to comprise a plural form, unlessspecified otherwise in the context. It should also be known that thewording “comprise” used in the description indicates that the specifiedfeature, integer, step, operation, unit and/or component are present,without excluding the presence or adding of one or more other features,integers, steps, operations, units and/or components, as well as/or acombination thereof.

The present invention is described with reference to the specificembodiments in the foregoing description. However, those skilled in theart could understand that various modifications and changes may be madewithout departing from the scope of the present invention as defined bythe appended claims.

The exemplary embodiments are described in the following:

1. A device for use in a Multi-Input Multi-Output (MIMO) wirelesscommunication system, comprising:

a matching unit configured to determine a matching degree of channelestimation information of a communication device to be scheduled withone or more reference vectors included in a reference vector group,wherein the reference vector group depends on an antenna arrayconfiguration of the MIMO wireless communication system; and

a channel characteristic determining unit configured to determinecorrelation information of the one or more reference vectors with thematching degree satisfying a predetermined condition as one or moreparameters reflecting channel characteristic(s) associated with thecommunication device.

2. The device according to embodiment 1, wherein, the channelcharacteristic determining unit is configured to determine one or morereference vectors with the matching degree being greater than apredetermined threshold, as one or more representative vectors of thecommunication device for specific transmission resources, and the one ormore parameters reflecting the channel characteristic(s) associated withthe communication device comprises the representative vector(s).

3. The device according to embodiment 1, further comprising acommunication device scheduling unit configured to schedule, based onthe channel characteristics associated with a plurality of communicationdevices to be scheduled, one or more of the plurality of communicationdevices.

4. The device according to embodiment 3, wherein, the communicationdevice scheduling unit is configured to schedule, for specifictransmission resources, the ones among the plurality of communicationdevices whose differences in channel characteristics between each othersatisfy a predetermined condition to perform transmission.

5. The device according to embodiment 1, further comprising apre-encoding unit configured to pre-encode, for a plurality ofcommunication devices which are simultaneously scheduled, transmissiondata of the scheduled communication devices based on channelcharacteristics associated with the plurality of communication devices.

6. The device according to embodiment 1, wherein, the reference vectorgroup comprises a plurality of reference vectors orthogonal to oneanother, the plurality of reference vectors corresponding to a pluralityof virtual channel vectors of the antenna array which are orthogonal toone another.

7. The device according to embodiment 1, wherein, the reference vectorgroup comprises a plurality of reference vectors, wherein, the pluralityof reference vectors correspond to virtual channel vectors of theantenna array in a plurality of maximum antenna gain directions.

8. The device according to embodiment 2, wherein, the communicationdevice scheduling unit is configured to schedule communication deviceshaving no identical representative vector or having relatively lessidentical representative vectors to perform transmission on the specifictransmission resources.

9. The device according to embodiment 2, further comprising apre-encoding matrix generating unit configured to calculate, in a casewhere the communication device scheduling unit schedules communicationdevices having identical representative vectors to perform transmissionon the specific transmission resources, a pre-encoding matrix for thecommunication devices having identical representative vectors based onthe channel characteristics, to reduce interference on the communicationdevices having identical representative vectors.

10. The device according to embodiment 2, wherein, the predeterminedthreshold is set in association with at least one of a channel gain, ascheduling requirement for each communication device to be scheduled,and a fairness principle.

11. The device according to embodiment 1, wherein, the channelestimation information is long-term channel statistical information orchannel state information.

12. A wireless communication method for a Multi-Input Multi-Output(MIMO) wireless communication system, the method comprising:

determining a matching degree of channel estimation information of acommunication device to be scheduled with one or more reference vectorsincluded in a reference vector group, wherein the reference vector groupdepends on an antenna array configuration of the MIMO wirelesscommunication system; and

determining correlation information of one or more reference vectorswith the matching degree satisfying a predetermined condition as one ormore parameters reflecting channel characteristic(s) associated with thecommunication device.

13. A device for use in a Multi-Input Multi-Output (MIMO) wirelesscommunication system, comprising:

a receiving unit configured to receive configuration information of anantenna array; and

a generating unit configured to generate a reference vector group basedon the configuration information.

14. The device according to embodiment 13, wherein, any two of referencevectors in the reference vector group are orthogonal to each other.

15. The device according to embodiment 14, wherein, the generating unitgenerates the reference vector group based at least on antenna numberinformation in the configuration information.

16. The device according to embodiment 15, wherein, a dimension numberof the reference vectors in the reference vector group is equal to theantenna number.

17. The device according to embodiment 15, wherein, the generating unitgenerates the reference vector group further based on information on ageometrical shape of the antenna array in the configuration information.

18. A device for use in a Multi-Input Multi-Output (MIMO) wirelesscommunication system, comprising:

one or more processors configured to implement a method comprising:

determining a matching degree of channel estimation information of acommunication device to be scheduled with one or more reference vectorsincluded in a reference vector group, wherein the reference vector groupdepends on an antenna array configuration of the MIMO wirelesscommunication system; and

determining correlation information of one or more reference vectorswith the matching degree satisfying a predetermined condition, as one ormore parameters reflecting channel characteristic(s) associated with thecommunication device.

19. A device for use in a Multi-Input Multi-Output MIMO wirelesscommunication system, comprising:

one or more processors configured to implement a method comprising:

aqcuiring configuration information of an antenna array; and

generating a reference vector group based on the configurationinformation.

20. A non-transitory computer readable storage device havinginstructions stored therein that when executed by processing circuitryperform a communications method, the method comprising:

determining a matching degree of channel estimation information of acommunication device to be scheduled with one or more reference vectorsincluded in a reference vector group, wherein the reference vector groupdepends on an antenna array configuration of the MIMO wirelesscommunication system; and

determining correlation information of one or more reference vectorswith the matching degree satisfying a predetermined condition, as one ormore parameters reflecting channel characteristic(s) associated with thecommunication device.

What is claimed is:
 1. A device for use in a Multi-Input Multi-OutputMIMO wireless communication system, comprising: a matching unitconfigured to determine a matching degree of channel estimationinformation of a communication device to be scheduled with one or morereference vectors included in a reference vector group, wherein thereference vector group depends on an antenna array configuration of theMIMO wireless communication system; and a channel characteristicdetermining unit configured to determine correlation information of theone or more reference vectors with the matching degree satisfying apredetermined condition as one or more parameters reflecting channelcharacteristic(s) associated with the communication device.
 2. Thedevice according to claim 1, wherein, the channel characteristicdetermining unit is configured to determine one or more referencevectors with the matching degree being greater than a predeterminedthreshold, as one or more representative vectors of the communicationdevice for specific transmission resources, and the one or moreparameters reflecting the channel characteristic(s) associated with thecommunication device comprises the representative vector(s).
 3. Thedevice according to claim 1, further comprising a communication devicescheduling unit configured to schedule, based on the channelcharacteristics associated with a plurality of communication devices tobe scheduled, one or more of the plurality of communication devices. 4.The device according to claim 3, wherein, the communication devicescheduling unit is configured to schedule, for specific transmissionresources, the ones among the plurality of communication devices whosedifferences in channel characteristics between each other satisfy apredetermined condition to perform transmission.
 5. The device accordingto claim 1, further comprising a pre-encoding unit configured topre-encode, for a plurality of communication devices which aresimultaneously scheduled, transmission data of the scheduledcommunication devices, based on channel characteristics associated withthe plurality of communication devices.
 6. The device according to claim1, wherein, the reference vector group comprises a plurality ofreference vectors orthogonal to each other, the plurality of referencevectors corresponding to a plurality of virtual channel vectors of theantenna array which are orthogonal to each other.
 7. The deviceaccording to claim 1, wherein, the reference vector group comprises aplurality of reference vectors, wherein, the plurality of referencevectors correspond to virtual channel vectors of the antenna array in aplurality of maximum antenna gain directions.
 8. The device according toclaim 2, wherein, the communication device scheduling unit is configuredto schedule communication devices having no identical representativevectors or having relatively less identical representative vectors toperform transmission on the specific transmission resources.
 9. Thedevice according to claim 2, further comprising a pre-encoding matrixgenerating unit configured to calculate, in a case where thecommunication device scheduling unit schedules communication deviceshaving identical representative vectors to perform transmission on thespecific transmission resources, a pre-encoding matrix for thecommunication devices having identical representative vectors, based onthe channel characteristics, to reduce interference on the communicationdevices having identical representative vectors.
 10. The deviceaccording to claim 2, wherein, the predetermined threshold is set inassociation with at least one of a channel gain, a schedulingrequirement for each communication device to be scheduled and a fairnessprinciple.
 11. The device according to claim 1, wherein, the channelestimation information is long-term channel statistical information orchannel state information.
 12. A wireless communication method for aMulti-Input Multi-Output MIMO wireless communication system, the methodcomprising: determining a matching degree of channel estimationinformation of a communication device to be scheduled with one or morereference vectors included in a reference vector group, wherein thereference vector group depends on an antenna array configuration of theMIMO wireless communication system; and determining correlationinformation of one or more reference vectors with the matching degreesatisfying a predetermined condition, as one or more parametersreflecting channel characteristic(s) associated with the communicationdevice.
 13. A device for use in a Multi-Input Multi-Output MIMO wirelesscommunication system, comprising: a receiving unit configured to receiveconfiguration information of an antenna array; and a generating unitconfigured to generate a reference vector group based on theconfiguration information.
 14. The device according to claim 13,wherein, any two of reference vectors in the reference vector group areorthogonal.
 15. The device according to claim 14, wherein, thegenerating unit generates the reference vector group based at least onantenna number information in the configuration information.
 16. Thedevice according to claim 15, wherein, a dimension number of thereference vectors in the reference vector group is equal to the antennanumber.
 17. The device according to claim 15, wherein, the generatingunit generates the reference vector group based further on informationon a geometrical shape of the antenna array in the configurationinformation.
 18. A device for use in a Multi-Input Multi-Output MIMOwireless communication system, comprising: one or more processorsconfigured to implement a method comprising: determining a matchingdegree of channel estimation information of a communication device to bescheduled with one or more reference vectors included in a referencevector group, wherein the reference vector group depends on an antennaarray configuration of the MIMO wireless communication system; anddetermining correlation information of one or more reference vectorswith the matching degree satisfying a predetermined condition, as one ormore parameters reflecting channel characteristic(s) associated with thecommunication device.
 19. A device for use in a Multi-Input Multi-OutputMIMO wireless communication system, comprising: one or more processorsconfigured to implement a method comprising: aqcuiring configurationinformation of an antenna array; and generating a reference vector groupbased on the configuration information.
 20. A non-transitory computerreadable storage device having instructions stored therein that whenexecuted by processing circuitry perform a communications method, themethod comprising: determining a matching degree of channel estimationinformation of a communication device to be scheduled with one or morereference vectors included in a reference vector group, wherein thereference vector group depends on an antenna array configuration of theMIMO wireless communication system; and determining correlationinformation of one or more reference vectors with the matching degreesatisfying a predetermined condition, as one or more parametersreflecting channel characteristic(s) associated with the communicationdevice.